Boil the kettle and place the cashews in a heatproof bowl. Pour boiling water over the cashews to cover and set aside for at least 10 minutes (longer is fine too if it is convenient).
When the mixture is cool, drain off the water and place the cashews in a high-speed food processor (I use a NutriBullet). Weigh in the water and blitz until the cashews are completely combined and you have a foamy, creamy milk.
Weigh the sugar into a medium saucepan and mix in the xanthan gum. This helps distribute it evenly so it won’t clump up later. Use a silicone spatula to keep moving the sugar around as you add the cashew milk. Make sure you get the edges of the saucepan as the sugar xanthan mix tends to clump up around the edges.
Add the remaining ingredients and place over a medium heat. Cook for 1-2 minutes or just until the sugars have both completely dissolved. Set aside to cool a little.
Make sure the bottom mechanism of the Ninja Swirl tub is closed before pouring in the mixture. It should come up to the fill line.
Place the mixture in the freezer for 24 hours with the lid off. Leaving the lid off can help minimise the risk of the mixture developing a hump which can damage your machine.
When ready to eat, process the mixture using the SCOOP and ICE CREAM functions. I always use SCOOP for high fat mixtures as the SOFT SERVE function tends to over-spin them.
If you’re eating it as a scoop, you are good to go. If you want to make soft serve, swap the lids and place the piping nozzle on. Use the lever to pull the soft serve. If you get an error message, allow the mixture to thaw for 5-10 minutes before continuing.
If you are making soft serve, know that the machine doesn't process the mixture in the bottom of the tub and it tends to be a bit icy.